I figure, to be a real KDB expert, I should learn K, right? So I can write some fast functions and understand how things actually work, etc.?
I found this definition of factorial that does not work, ...

Given (rectangular) adjacency matrix m, how to construct adjacency list in q language?
In QIdioms wiki I've found solution in the k language which when run through q console with k) command gives me '...

Is there a functional form equivalent to the following?
trades:([]date:`date$();time:`time$();sym:`symbol$();price:`real$();size:`int$(); cond:`char$())
Assuming the function name is "ct"...
trades:...

I have a table with time series data grouped by name (with some dates missing), and would like to transform the table by creating a column for each group containing that group's data. In other words, ...

I'm trying to learn APL (Kona), and I'm looking for example projects so I can get an understanding of how an experienced APL'er would organize his/her code.
Any open source projects would be helpful ...

The array-language landscape, while fascinating, is confusing to no end. Is there a reason to pick one of J or K or APL or A? None of these options seem to be open-sourced -- are there open sourced ...

I know all 3 are related, and I've seen quite a few answers for problems in Project Euler written in J, and a few written K. What I'm wondering is, which would you suggest learning, and where would ...